What is a bomb cyclone and what states is it hitting?

The East Coast is bracing for a severe winter storm this weekend. A nor’easter dubbed a “bomb cyclone” is expected to charge up the East Coast Friday night until Sunday, covering the mid-Atlantic and New England states in a heavy blanket of snow.  

“Confidence is increasing that a significant winter storm will create considerable impacts Friday through the weekend from the Mid-Atlantic through the Northeast,” the National Weather Service’s Weather Prediction Center said. 

The storm, dubbed Winter Storm Kenan, will begin to batter the East Coast Friday night into Saturday morning and will impact over 75 million people, according to CNN. 

What is a bomb cyclone?

A bomb cyclone is a winter hurricane, which the National Oceanic and Atmospheric Administration said is created by a process known as bombogenesis. 

A bomb cyclone occurs when a midlatitude cyclone rapidly intensifies, dropping at least 24 millibars — a measure for atmospheric pressure — over 24 hours. The NOAA said this happens when a cold air mass collides with a warm air mass, such as air over warm ocean waters. This process is called bombogenesis, which creates what is known as a bomb cyclone.

What states will it hit?

The National Weather Service has issued winter storm watches throughout North Carolina, Virginia, Maryland, Delaware, New Jersey, Pennsylvania, New York, Connecticut, Rhode Island, Massachusetts, Maine and Illinois.

In an advisory, the Weather Prediction Center (WPC) said the “powerful winter storm” will produce “significant impacts across parts of New England and coastal Mid-Atlantic/Northeast on Saturday.”

According to WPC, the storm developed off the Atlantic coast of Florida on Friday.

“This low will rapidly intensify as it travels north throughout the day. Moderate to heavy snow and gusty winds are forecast to materialize along the Mid-Atlantic and Northeast coasts this evening as the low arrives off the coast of North Carolina,” the advisory adds.

“Some moderate to heavy amounts are also likely to spread into parts of the Central and Southern Appalachians. Heavy snow and intense winds are then expected to develop over New England on Saturday as the Nor’easter continues to intensify off the Northeast coast.”

A Winter Weather Advisory has also been issued for Washington, D.C., and will be in effect from 4 p.m. on Friday until 4 a.m. on Saturday. A total snow accumulation of 1-3 inches is possible.

Virginia Gov. Glenn Youngkin (R) also issued a state of emergency on Thursday in advance of the storm.

What to expect?

The heaviest snow is anticipated in New England, according to the weather agency.

Eastern Massachusetts, Long Island, Rhode Island and Cape Cod may get more than 20 inches of snow, while parts of Connecticut could see up to 12 inches of snow. The New York City area could see 6 inches or more, according to CNN. 

Blizzard conditions are forecast from eastern Long Island through much of coastal New England, particularly from southeast Maine to Cape Cod, making travel nearly impossible.

“Significant beach erosion and coastal flooding will also be a concern. Winter Storm Watches and Warnings are in effect for much of the coastal Mid-Atlantic up into the coastal Northeast. Winter weather advisories and warnings are in effect for parts of the Central/Southern Appalachians,” the Weather Prediction Center said.

The heaviest snowfall is likely to fall across a swath extending from the Eastern Shore of Maryland up through most of Maine, where 6-12 inches are likely. Parts of coastal New England, where blizzard conditions are forecast, may see between 1-2 feet of snow with higher amounts possible in certain areas, such as coastal Massachusetts.

The advisory adds that temperatures will be 15-25 degrees below average in most places. 

AccuWeather meteorologists warned that the storm could shut down Boston’s Logan International Airport, among others, and result in flight cancellations in New York City, Philadelphia and Washington, D.C.